The AOR VI8200 is an optional plug-in slot card for the AR8200 series that performs voice inversion decoding. It recovers intelligible audio from certain types of analogue voice transmissions which would otherwise sound scrambled. They operate by splitting up the audio spectrum and flipping the upper and lower tones around a certain frequency point. The VI8200 enables 157 different flip points to be selected in the audio frequency range of 2.4 kHz to 5.6 kHz. The table below illustrates the relationship between value and flip frequency.